require 'prime'
m = gets.to_i
n = gets.to_i
c = gets.split.map(&:to_i)

dp = Array.new(m+1, -1)
dp[m] = 0
m.downto(1) { |i|
	next if m[i] < 0
	c.each { |j|
		dp[i-j] = [dp[i-j], dp[i]+1].max if dp[i] >= 0 && j <= i
	}
}

puts dp.max + dp.each_with_index.inject(0) {|p,c| p + (c[1].prime? && c[0] > 0 ? c[0] : 0)}